This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 675 |
| 7 | 3527 |
| 8 | 15484 |
| 9 | 56917 |
| 10 | 179719 |
| 11 | 500864 |
| 12 | 1260117 |
| 13 | 2913132 |
| 14 | 6274230 |
| 15 | 12726573 |
| 16 | 24521243 |
| 17 | 45190897 |
| 18 | 80108200 |
| 19 | 137224138 |
| 20 | 228026582 |
| 21 | 368765112 |
| 22 | 581994117 |
| 23 | 898492563 |
| 24 | 1359625566 |
| 25 | 2020220021 |
| 26 | 2952034021 |
| 27 | 4247907652 |
| 28 | 6026690971 |
| 29 | 8439053564 |